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/*
* Copyright (C) 2002 Free Software Foundation, Inc.
* (originally part of the GNU C Library and Userspace RCU)
* Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
*
* Copyright (C) 2009 Pierre-Marc Fournier
* Conversion to RCU list.
* Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see
* <http://www.gnu.org/licenses/>.
*/
#ifndef LIST_H
#define LIST_H 1
/*
* The definitions of this file are adopted from those which can be
* found in the Linux kernel headers to enable people familiar with the
* latter find their way in these sources as well.
*/
/* Basic type for the double-link list. */
struct list_head {
struct list_head *next, *prev;
};
/* avoid conflicts with BSD-only sys/queue.h */
#undef LIST_HEAD
/* Define a variable with the head and tail of the list. */
#define LIST_HEAD(name) \
struct list_head name = { &(name), &(name) }
/* Initialize a new list head. */
#define INIT_LIST_HEAD(ptr) \
(ptr)->next = (ptr)->prev = (ptr)
#define LIST_HEAD_INIT(name) { &(name), &(name) }
/* Add new element at the head of the list. */
static inline void list_add(struct list_head *newp, struct list_head *head)
{
head->next->prev = newp;
newp->next = head->next;
newp->prev = head;
head->next = newp;
}
/* Add new element at the tail of the list. */
static inline void list_add_tail(struct list_head *newp, struct list_head *head)
{
head->prev->next = newp;
newp->next = head;
newp->prev = head->prev;
head->prev = newp;
}
/* Remove element from list. */
static inline void __list_del(struct list_head *prev, struct list_head *next)
{
next->prev = prev;
prev->next = next;
}
/* Remove element from list. */
static inline void list_del(struct list_head *elem)
{
__list_del(elem->prev, elem->next);
}
/* Remove element from list, initializing the element's list pointers. */
static inline void list_del_init(struct list_head *elem)
{
list_del(elem);
INIT_LIST_HEAD(elem);
}
/* Delete from list, add to another list as head. */
static inline void list_move(struct list_head *elem, struct list_head *head)
{
__list_del(elem->prev, elem->next);
list_add(elem, head);
}
/* Replace an old entry. */
static inline void list_replace(struct list_head *old, struct list_head *newp)
{
newp->next = old->next;
newp->prev = old->prev;
newp->prev->next = newp;
newp->next->prev = newp;
}
/* Join two lists. */
static inline void list_splice(struct list_head *add, struct list_head *head)
{
/* Do nothing if the list which gets added is empty. */
if (add != add->next) {
add->next->prev = head;
add->prev->next = head->next;
head->next->prev = add->prev;
head->next = add->next;
}
}
/* Get typed element from list at a given position. */
#define list_entry(ptr, type, member) \
((type *) ((char *) (ptr) - offsetof(type, member)))
/* Get first entry from a list. */
#define list_first_entry(ptr, type, member) \
list_entry((ptr)->next, type, member)
/* Iterate forward over the elements of the list. */
#define list_for_each(pos, head) \
for (pos = (head)->next; pos != (head); pos = pos->next)
/*
* Iterate forward over the elements list. The list elements can be
* removed from the list while doing this.
*/
#define list_for_each_safe(pos, p, head) \
for (pos = (head)->next, p = pos->next; \
pos != (head); \
pos = p, p = pos->next)
/* Iterate backward over the elements of the list. */
#define list_for_each_prev(pos, head) \
for (pos = (head)->prev; pos != (head); pos = pos->prev)
/*
* Iterate backwards over the elements list. The list elements can be
* removed from the list while doing this.
*/
#define list_for_each_prev_safe(pos, p, head) \
for (pos = (head)->prev, p = pos->prev; \
pos != (head); \
pos = p, p = pos->prev)
static inline int list_empty(struct list_head *head)
{
return head == head->next;
}
static inline void list_replace_init(struct list_head *old,
struct list_head *newp)
{
struct list_head *head = old->next;
list_del(old);
list_add_tail(newp, head);
INIT_LIST_HEAD(old);
}
/*
* This is exactly the same as a normal list_head, except that it can be
* declared volatile (e.g., if you have a list that may be accessed from signal
* handlers).
*/
struct volatile_list_head {
volatile struct volatile_list_head *next, *prev;
};
#define VOLATILE_LIST_HEAD(name) \
volatile struct volatile_list_head name = { &(name), &(name) }
static inline void __volatile_list_del(volatile struct volatile_list_head *prev,
volatile struct volatile_list_head *next)
{
next->prev = prev;
prev->next = next;
}
static inline void volatile_list_del(volatile struct volatile_list_head *elem)
{
__volatile_list_del(elem->prev, elem->next);
}
static inline int volatile_list_empty(volatile struct volatile_list_head *head)
{
return head == head->next;
}
static inline void volatile_list_add(volatile struct volatile_list_head *newp,
volatile struct volatile_list_head *head)
{
head->next->prev = newp;
newp->next = head->next;
newp->prev = head;
head->next = newp;
}
#endif /* LIST_H */